The story begins in March 1968, when a Soviet Golf II submarine — carrying nuclear ballistic missiles tipped with four-megaton warheads and a seventy-person crew — suffered an internal explosion while on a routine patrol mission and sank in the Pacific Ocean, some 1,900 nautical miles northwest of Hawaii. The Soviets undertook a massive, two-month search, but never found the wreckage. However, the unusual Soviet naval activity prompted the U.S. to begin its own search for the sunken vessel, which was found in August 1968.

The submarine, if recovered, would be a treasure trove for the intelligence community. Not only could U.S. officials examine the design of Soviet nuclear warheads, they could obtain cryptographic equipment that would allow them to decipher Soviet naval codes. And so began Project AZORIAN. The U.S. intelligence community commissioned Howard Hughes to construct a massive vessel — dubbed the Hughes Glomar Explorer (HGE) — to recover the sub. The ensuing salvage operation, which began in 1974, was only a partial success; the U.S. was planning to embark on a second attempt when, in 1975, the story was leaked to the press, and the operation was canceled.